It is well known and accepted in the art that the transport and industrial utilization of elastomers in the form of small particles, such as powders, large particles or crumbs or granules, are particularly convenient for ease of handling and use in the manufacture of many end products, either alone or in combination with other materials. Unfortunately, these elastomeric particles present a great difficulty in that they tend to agglomerate irreversibly during industrial transformation operations and during transport or storage of the elastomeric particles. This agglomeration makes the product most undesirable for use in all or most commercial operations.
In order to overcome these agglomerations, it has been the practice to use flow control agents in the processing, dispensing and storage of elastomeric particulate materials, which agents can physically separate larger particles thereby preventing their agglomeration. By flow control agents is meant organic or mineral powders or dusts, such as talc, which separate the elastomeric particles from one another. However, elastomeric particles, such as powdered and crumb rubbers, are very prone to agglomeration during storage, even when such material is treated with flow control agents, such as talc. This is so, since it has been found that the additive employed to separate the elastomer particles is itself in the form of fine powder, for example, talc, and thus separates from the larger elastomer particles and gives a final non-homogeneous and powdery product. As a result, this powdery product cannot be adequately and economically handled in the usual commercial handling equipment, such as molding apparatus, and the like. In addition, the final product may be heterogeneous and the foundation of dust associated therewith presents risks for the health of the operators of the equipment.
It has also been proposed, in order to overcome the problem of agglomeration, to apply a resin coating to the elastomeric particles. Here again, such techniques have met with difficulties since, in many instances, the resin which covered the particles had a tendency to be separated from the elastomeric particles. The resin collects in the bottom of the storage container and is designated by the term "fines". The presence of fines causes the elastomeric particles to again agglomerate and when the product is worked, or employed on commercial finishing equipment, the fines result in a heterogeneous product which is unacceptable. This modification of the elastomer particles by coating with a resin is commonly known as "encapsulation" and care must be taken so as not to adversely affect or alter the processing characteristics of the elastomer. On the other hand, if one could find the proper encapsulating material, which is compatible with the end use characteristics of the elastomer and does not substantially modify its intrinsic properties, it would greatly enhance the usefulness of elastomers or free flowing powdered and crumb rubbers.